Nearly a mile across and 600ft deep, the second-most impressive hole in Arizona was formed by a fiery meteor that screamed into the atmosphere about 50,000 years ago, when giant sloths lived in these parts. Meteor Crater, 40 miles east of Flagstaff, is an out-of-this-world site for those with a thimbleful of imagination. There are lookout points around the crater's edge (but no hiking to the bottom) and the visitor center is as fun as it is informative.
Take exit 233 off I-40.